Bat for baseball or softball

ABSTRACT

A bat for baseball or softball of the present invention includes a first tube having an impact part, a step part and a stopper part, a cylindrical second tube, a fixing component being inserted between the first tube and second tube, the step part having an exterior diameter larger than that of the impact part and smaller than an interior diameter of the second tube, the stopper part having an exterior diameter larger than that of the step part and large than the interior diameter of the second tube, the second tube is held of an exterior periphery of the impact part, one end of the second tube is fixed between the stopper part and the step part by an adhesive and the other end is fixed by an adhesive on the fixing component, and a crevice is formed between the first tube and the second tube.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2008-123266, filed on May, 9,2008, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to improving the rebound characteristics of a batfor baseball or softball.

2. Description of the Related Art

Conventionally, the flying distance of a ball is thought to be extendedwhen hit by a high strength bat. This is because it was considered thata bat with a high degree of strength has excellent reboundcharacteristics and the flying distance of a ball depended solely onthese rebound characteristics of the bat. However, in recent years, itis understood that a bat which can reduce the consumption of impactenergy as ball transformation energy when a ball and bat collide, canextend the flying distance of a ball. In addition, it is understood thatthe higher the rebound force/power of the bat itself, the further theflying distance of a ball is extended. Thus, as shown in Japanese LaidOpen Patent 2001-79131, a double layered bat formed by arranging afurther thin metal tube (called “exterior tube” and “interior tube”respectively) on the exterior or the interior of the body of a metal batis proposed. That is, a crevice is arranged between the bat body and theexterior tube or the bat body and the interior tube. In this way, anattempt is made to extend the flying distance of a ball by reducing theconsumption of impact energy as ball transformation energy by bending ofa bat's thin tube when a ball is hit.

FIG. 11 is a longitudinal direction notch sectional view and a crosssectional view of the line A-A′ in a width direction of one example of adouble layered bat. The bat in FIG. 11 is comprised from a bat tip part1, a bat impact part 2, a bat taper part 3 and a bat grip part 4. Anexterior tube 20 fits onto the bat from the bat tip part 1 up to the battaper part 3. In the bat taper part 3, the exterior tube 20 is latchedto a hollow for latching 70 which is arranged on the bat by a swagingprocess or spinning process. At this time, the exterior tube 20 islatched so that a fixed crevice is arranged between the bat and theexterior tube 20. Here the grip part 4 is the part of the bat which isheld by a batter and is the thinnest part of the bat which extends to apredetermined length from the end of the grip. The taper part 3 is thepart which has a diameter which gradually becomes larger from the grippart 4. In addition, the bat tip part 1 is the part which is formed by aresin for example, and is the end of the bat located in the furthestposition from the grip end. The bat impact part 2 is the part except thebat tip part 1, the bat taper part 3 and the bat grip part 4, and whichextends to a predetermined length towards the bat tip part 1 from thewidest part of the taper part 3 part (in the case of a double layeredbat, both an exterior tube and an interior tube of a double layeredstructure located at the part which extends to a predetermined lengthtowards the bat tip part 1 from the widest part of the taper part 3part). The bat impact part 2 is generally the part which is suitable forhitting a ball. Furthermore, depending on the manufacturing method, thetip part is sometimes formed as a part of the bat impact part 2 frommetal and in this case, the bat is comprised of the bat impact part 2,the bat taper part 3 and the bat grip part 4.

This double layered bat requires latching two tubes during finalprocessing by a swaging process for example. In this case, in order toremove processing distortions, a heat treatment is performed afterswaging processing and stress must be released. However, control of aheat treatment of a part having a double layered structure is difficultand securing sufficient strength and durability is also difficult.Particularly, in the case where the material of the bat body andexterior tube or bat body and interior tube are different, because themelting point of each material is also different, control of thetemperature and time of a heat treatment becomes complex.

However, as another approach, a recess part is arranged in the metal batand a layer of urethane is formed on this recess part, as shown inJapanese Laid Open Patent 2005-305146. In the present specification,this type of bat is called a hybrid type double layered bat.

FIG. 12 is a longitudinal direction notch sectional view and a crosssectional view of the line B-B′ in a width direction of one example of ahybrid type double layered bat. In FIG. 12, the diameter of the batimpact part 2 of the bat body 10 is reduced smoothly by a swagingprocess for example, from a boundary with the bat tip part 1 and from aboundary with the bat taper part 3 in the direction of the interior ofthe bat impact part 2. Then, a flexible layer of urethane 101 is formedto cover/enclose the bat body 10 and a hard layer of urethane 102 isformed on the exterior surface. In this hybrid type bat, when a ballcollides with the bat, the two layers of urethane (101 and 102) contractand consumption of the impact energy as ball transformation energy isreduced as much as possible and the flying distance of the ball can beextended. However, because an urethane layer deteriorates by seculardistortion, the durability of the bat is inferior compared to a metalmanufactured bat. In addition, the bat also suffered from an increase inmiss hits.

Thus, as shown in Japanese Laid Open Patent 2008-29620, a double layeredbat was manufactured using a fixing component.

BRIEF SUMMARY OF THE INVENTION

A bat for baseball or softball related to one embodiment of the presentinvention includes; a first tube having a grip part, a taper part, animpact part, a tip part, a step part having a larger exterior diameterthan an exterior diameter of the impact part and the first tube alsoincluding a stopper part having a larger exterior diameter than theexterior diameter of the step part; a cylindrical second tube having twoends which are open, and having an interior diameter which is largerthan the exterior diameter of the step part of the first tube andsmaller than the exterior diameter of the stopper part of the firsttube; a fixing component including a body part and an insertion part,the insertion part being inserted between the first tube and the secondtube, the fixing component latching the second tube to an exteriorperiphery of the first tube; and a crevice located between the firsttube and the second tube, the crevice being formed by the second tubebeing attached to an exterior periphery of the impact part of the firsttube, one end of the second tube being fixed between the step part ofthe first tube and the stopper part by an adhesive, and the other end ofthe second tube being fixed by the adhesive with the insertion part ofthe fixing component, the fixing component being inserted between thesecond tube and the first tube.

A bat for baseball or softball related to one embodiment of the presentinvention includes; a first tube having a grip part, a taper part, animpact part and a tip part, a step part having a larger exteriordiameter than an exterior diameter of the impact part, a first stopperpart having a larger exterior diameter than an exterior diameter of thestep part and the first tube also including a second stopper part havinga larger exterior diameter than the exterior diameter of the firststopper part; a cylindrical second tube having two ends which are open,and having an interior diameter which is larger an exterior diameter ofthe step part of the first tube and smaller than the exterior diameterof the first stopper part of the first tube; a cylindrical third tubehaving two ends which are open, and also having an interior diameterwhich is larger than an exterior diameter of the second tube and smallerthan the exterior diameter of the second stopper part of the first tube;a fixing component including a body part, an insertion part and a fixingcomponent stopper part, the insertion part being inserted between thefirst tube and the second tube, and the fixing component stopper partwhich forms a crevice between the second tube and the third tube, thefixing component latching the second tube and the third tube to anexterior periphery of the first tube; a first crevice located betweenthe second tube and the first tube, the first crevice being formed bythe second tube being attached to an exterior periphery of the impactpart of the first tube, one end of the second tube being fixed betweenthe step part of the first tube and the first stopper part by anadhesive, and the other end of the second tube being fixed by theadhesive with the insertion part of the fixing component, the fixingcomponent being inserted between the second tube and the first tube; anda second crevice located between the third tube and the second tube, thesecond crevice being formed by the third tube being attached to anexterior periphery of the second tube, one end of the third tube beingfixed between the first stopper part of the first tube and the secondstopper part by the adhesive and the other end of the third tube beingfixed by the adhesive with the fixing component stopper part of thefixing component.

A bat for baseball or softball related to one embodiment of the presentinvention includes; a first tube having a grip part, a taper part, animpact part, a tip part, a step part having a larger exterior diameterthan an exterior diameter of the impact part and the first tube alsoincluding a stopper part having a larger exterior diameter than theexterior diameter of the step part; a plurality of cylindrical secondtubes each having two ends respectively, the ends being open, and eachof the plurality of second tubes having an interior diameter and anexterior diameter which are the same respectively, the interior diameterof each of the plurality of second tubes being larger than the exteriordiameter of the step part of the first tube and smaller than theexterior diameter of the stopper part of the first tube, and at leastone of the plurality of second tubes being formed from a material whichis different to the other tubes; a first fixing component including abody part and an insertion part, the insertion part being insertedbetween the first tube and the second tube, the first fixing componentlatching the second tube to an exterior periphery of the first tube; asecond fixing component latching the plurality of second tubes to theexterior periphery of the first tube; and a crevice located between thefirst tube and the plurality of second tubes, the crevice being formedby each of the plurality of second tubes being attached to the exteriorperiphery of the impact part of the first tube, an end of one of theplurality of second tubes being fixed between the step part of the firsttube and the stopper part by an adhesive, the other end of one of theplurality of second tubes being fixed by the adhesive with the secondfixing component, an end of another one of the plurality of second tubesbeing fixed by the adhesive with the second fixing component, the otherend of another one of the plurality of second tubes being fixed by theadhesive with the first fixing component, and both ends of yet anotherone or more second tubes of the plurality of second tubes being fixed bythe adhesive with the second fixing component.

In addition, the bat for baseball or softball according to thisinvention, may further comprise a cap, the cap having a cap tip part, arecessed part and a fixing part, a tip of the tip part of the first tubehaving a curled part which curves inwards, an exterior diameter of thefixing part of the cap being smaller than an interior diameter of thefirst tube from the curled part to the stopper part, and an exteriordiameter of the recessed part of the cap being smaller than an interiordiameter of the curled part of the first tube and the recessed partbeing latched by the curled part.

The bat for baseball or softball according to this invention, wherein atip of the tip part may curve inwards and may be closed.

The bat for baseball or softball according to this invention, mayfurther comprise a spacer, the spacer being inserted between the firsttube and the second tube, the first tube includes a stopper part havinga larger exterior diameter than an exterior diameter of the impact partand a larger exterior diameter than an interior diameter of the secondtube, and the second tube is attached to an exterior periphery of theimpact part of the first tube, and one end of the second tube is fixedto a tip of a tip part side of the impact part of the first tube by theadhesive and the spacer, and the other end of the second tube beingfixed by the adhesive with the insertion part of the fixing component,the fixing component being inserted between the second tube and thefirst tube, and the crevice being formed between the first tube and thesecond tube.

The bat for baseball or softball according to this invention, whereinthe first tube may include a groove in a place of a taper part side ofthe impact part, the fixing component further having a protrusion parton a side in which the insertion part faces a first tube, the fixingcomponent being inserted between the first tube and the second tube, andthe protrusion part being fitted with the groove of the first tube.

The bat for baseball or softball according to this invention, whereinthe first tube may be formed from an aluminum alloy or an alloy steeland the second tube may be formed from titanium, a titanium alloy, amagnesium alloy or an alloy steel.

The bat for baseball or softball according to this invention, whereinthe first tube may further include a second step part having a largerexterior diameter than an exterior diameter of the impact part, theexterior diameter of the second step part being smaller than an interiordiameter of the second tube, and also includes a second stopper parthaving a larger exterior diameter than the exterior diameter of thesecond step part, the exterior diameter of the second stopper part beinglarger than the interior diameter of the second tube, the second tube isattached to an exterior periphery of the impact part of the first tube,and wherein one end of the second tube is fixed by the adhesive betweenthe step part of the first tube and the stopper part of the first tube,the other end of the second tube is fixed by the adhesive between thesecond step part of the first tube and the second stopper part of thefirst tube, and the second stopper part is formed so that the secondstopper part has a larger exterior diameter than an interior diameter ofthe second tube after the second tube is fixed between the stopper partand the step part and also between the second step part and the secondstopper part.

The bat for baseball or softball according to this invention, whereinthe stopper part may be formed in a position at least 100 mm or morefrom a tip of the tip part of the first tube, and the second tube isarranged in the best position for an impact.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (a) shows a longitudinal direction notch sectional view of batfor baseball or softball related to embodiment one of the presentinvention.

FIG. 1 (b) shows a cross sectional view of the line α-α′ in a widthdirection of bat for baseball or softball related to embodiment one ofthe present invention.

FIG. 2 shows an enlarged cross sectional view in a longitudinaldirection of a bat tip part and a bat impact part of a bat for baseballor softball related to embodiment one of the present invention.

FIG. 3 shows an enlarged cross sectional view in a longitudinaldirection of a bat impact part and a taper part of a bat for baseball orsoftball related to embodiment one of the present invention.

FIG. 4 shows an enlarged cross sectional view in a longitudinaldirection of a bat tip part of a bat for baseball or softball related toexample one of embodiment one of the present invention.

FIG. 5 shows an enlarged cross sectional view in a longitudinaldirection of a bat impact part and a taper part of a bat for baseball orsoftball related to example two of embodiment one of the presentinvention.

FIG. 6 shows an enlarged cross sectional view in a longitudinaldirection of a bat tip part of a bat for baseball or softball related toexample three of embodiment one of the present invention.

FIG. 7 shows an enlarged cross sectional view in a longitudinaldirection of a bat tip part of a bat for baseball or softball related toexample three of embodiment one of the present invention.

FIG. 8 (a) shows a longitudinal direction notch sectional view of a batfor baseball or softball related to embodiment two of the presentinvention.

FIG. 8 (b) shows a cross sectional view of the line β-β′ in a widthdirection of a bat for baseball or softball related to embodiment two ofthe present invention.

FIG. 9 (a) shows a longitudinal direction surface view of a bat forbaseball or softball related to embodiment three of the presentinvention.

FIG. 9 (b) shows a longitudinal direction notch sectional view of a batfor baseball or softball related to embodiment three of the presentinvention.

FIG. 10 (a) shows a longitudinal direction surface view of a bat forbaseball or softball related to embodiment four of the presentinvention.

FIG. 10 (b) shows a longitudinal direction notch sectional view of a batfor baseball or softball related to embodiment four of the presentinvention.

FIG. 11 (a) shows a longitudinal direction notch sectional view of oneexample of a double layered bat.

FIG. 11 (b) shows a cross sectional view of the line A-A′ in a widthdirection of one example of a double layered bat.

FIG. 12 (a) shows a longitudinal direction notch sectional view of oneexample of a hybrid type double layered bat.

FIG. 12 (b) shows a cross sectional view of the line B-B′ in a widthdirection of one example of a hybrid type double layered bat.

DETAILED DESCRIPTION OF THE INVENTION Structure of a Double Layered Bat

The present invention can reduce the consumption of impact energy asball transformation energy and in particular a bat for baseball orsoftball is proposed in which the strength of the bat tip part isreinforced. Furthermore, in the present invention, a bat for baseball orsoftball is proposed which is inexpensive and can be easilymanufactured.

The bat for baseball or softball related to embodiment one of thepresent invention will be explained below based on the diagrams.Furthermore, the same structural components have the same symbols andthus an explanation of these components which overlap betweenembodiments will be omitted. FIG. 1 is a longitudinal direction notchsectional view and a cross sectional view of the line α-α′ in a widthdirection of bat for baseball or softball related to embodiment one ofthe present invention. In addition, FIG. 2 is an enlarged crosssectional view in a longitudinal direction of a bat tip part and a batimpact part of a bat for baseball or softball related to embodiment oneof the present invention. Furthermore, one example of a bat for baseballor softball of the present invention is shown in the embodiments.However, the bat for baseball or softball of the present invention isnot limited to these embodiments.

In FIG. 1, the bat for baseball or softball related to embodiment one ofthe present invention is roughly comprised of a first tube 15, a secondtube 20, a fixing component 30 and a cap 40. The first tube 15 includesa tip part 11, an impact part 12, a taper part 13 and a grip part 14 andthe second tube 20 is fixed to the exterior of the impact part 12 of thefirst tube 15. Furthermore, in embodiment one of the present invention,the second tube 20 is sometimes called an exterior tube 20. In addition,in the bat for baseball or softball related to embodiment one of thepresent invention, the impact part which hits a ball is formed as onepart comprising the impact part 12 of the first tube 15 and the secondtube 20, however, for the purposes of explanation, only this part of thefirst tube 15 is called the impact part 12 below.

in FIG. 1, the first tube 15 is the part which forms the center when aball is hit by a batter. The batter holds the grip part 14, swings thebat and hits a ball which is thrown. As stated above, the first tube 15is comprised of roughly four component parts, the tip part 11, theimpact part 12, the taper part 13 and the grip part 14 and is generallyformed as one body from an aluminum alloy or steel alloy in order tosecure lightness and strength. However, the bat is not limited to this.For example, the bat may also be formed by titanium or a titanium alloy.From the viewpoint of ease of manufacturing and cost, the material ofthe first tube 15 is preferably an A7000 aluminum alloy such as aluminumalloy AA7050, AA7046 regulated under the American Aluminum AssociationRegulation.

In embodiment one of the present invention, in order to achievelightness across an entire bat having a double layered structure, thefirst tube 15 is formed with a thickness of 1 mm-3 mm for example. Afterthe first tube 15 is formed from the above stated metal, a series ofheat treatments are performed to remove any processing distortions andsecure a certain level of strength. By this method, any stress isreleased and the first tube 15 becomes usable. Furthermore, the abovestated thickness is only an example and not limited to this.

The first tube 15 is formed by processing a thick cylindrical tube usinga process means such as a swaging process. In the present embodiment, atube of aluminum alloy having a diameter within the range of the largestdiameter of a bat regulated by baseball rules was used. The diameter ofthis tube is reduced by processing such as a swaging process from thetip part 11 towards the grip part 14 and the first tube 15 was formed.First, only a certain diameter of this tube was reduced at a first place81 located at a certain distance from the tip part 11 towards the grippart 14. This certain diameter is equal to the sum of the thickness ofthe second tube 20 which is the exterior tube and the thickness of anadhesive 50. This first place 81 in which the diameter has been reducedby processing is called a stopper part 18. It is possible to understandthe stopper part 18 in detail by referring to FIG. 2. After the exteriortube 20 is attached and the double layered bat is formed the stopperpart 18 plays the role of stopping the movement of the exterior tube 20towards the bat tip part side.

Furthermore, the diameter of the tube is gradually reduced to a certainheight (a certain diameter) from a second place 82 located a fixeddistance from the stopper part 18 towards the grip part 14 up to a thirdplace 83. This certain height is the height of a crevice 60 which isformed between the first tube 15 and the second tube 20 when the secondtube 20 is attached to the first tube 15 by the adhesive 50.Furthermore, the space between the second place 82 up to the third place83 is called a step part 17. It is possible to understand step part 17in detail by referring to FIG. 2. In addition, the space from thestopper part 18 of the first tube 15 up to the second place 82 is thepart in which the second tube 20 is later fixed by the adhesive 50. Inaddition, the space from the stopper part 18 up to the second place 82is a part which plays a role equal to the fulcrum of a spring when thesecond tube 20 bends at the time of an impact.

Next, the length equal to that of the impact part 12 is processed to thesame diameter from the third place 83 towards the grip part 14. Then,the diameter is gradually reduced by a swaging process towards the grippart 14 from a fourth place 84 which is located in a place the samelength as the impact part 12 from the third place 83 towards the grippart 14 and the taper part 13 and grip part 14 are formed. The grip endpart is sealed off by spinning processing. However, processing of thegrip end part is not limited to this. For example, a separate grip endpart formed in advance can be latched by a screw and adhesive orwelding. The method of forming the grip end can be appropriatelyselected. The tip of the tip part 11 is curved towards the interior ofthe bat to a certain length (below this process is called a curlingprocess) and the curled part 19 is formed. In other words, the tip ofthe tip part 11 is almost bent in a perpendicular direction towards theinterior of the bat. The length which is curved should be a lengthsufficient to latch the cap 40 which is processed by press fitprocessing, such as 3 mm-10 mm or more preferably 5 mm.

In addition, the method for forming the first tube 15 is not limited tothat stated above. That is, first, a desired first tube 15 may be formedin the following way. The diameter of one end of an open cylindricaltube which has an exterior diameter of the impact part 12 is reduced bya swaging process forming the taper part 13 and the grip part 14, andthe diameter of the other end of the open cylindrical tube is expandedtowards the tip part 11 by a diameter expanding process so that thestopper part 17 and step part 18 are formed. The method of forming thefirst tune 15 can be appropriately selected. Formation of the grip endby welding or screwing the grip end which is formed separately inadvance or by a spinning process, and formation of the curled part 19 bya curling process is the same. Furthermore, the diameter reducingprocess may be a method other than the above stated swaging process, forexample, a stepping process or a tapering process.

The first tube 15 of the bat for baseball or softball related toembodiment one of the present invention has a step part 17 and a stopperpart 18 by the above stated process. The exterior diameter of the firsttube 15 between the step part 17 and the stopper part 18 is larger thanthe exterior diameter of the impact part 12 and smaller than theinterior diameter of the second tube 20. However, the exterior diameterof the first tube 15 between the step part 17 and the stopper part 18 isslightly smaller than the interior diameter of the second tube 20.Therefore, the second tube 20 is inserted from the grip end side of thefirst tube 15, one end of the second tube 20 is fitted onto the exteriorof the impact part 12 of the first tube 15 by the adhesive 50 and thesecond tube 20 becomes fixed when the adhesive 50 hardens. In addition,the other end of the second tube 20 is fixed by the fixing component 20,which is explained in detail below, and the adhesive 50. Then, thesecond tube 20 is latched to the exterior of the impact part 12 of thefirst tube 15 and a crevice 60 of a certain height is formed between thesecond tube 20 and the first tube 15.

The exterior diameter of the stopper part 18 is larger than the interiordiameter of the second tube 20 and preferably should be the samediameter as the exterior diameter of the second tube 20. In this way,when the completed bat is swung, the second tube 20 tries to movetowards the tip part 11 by centrifugal force, however, the movement ofthe second tube 20 is completely halted by this stopper part 18. Thematerial of the first tube 15 and the second tube 20 is different, aswill be explained below, however, because both are formed from a metalalloy, there is no significant difference in a thermal expansioncoefficient. Therefore, the second tube 20 is completely fixed to theexterior of the impact part 12 of the first tube 15 and as long as thereis no damage to the tip part 11 of the first tube 15, the second tube 20will not jump out from the tip part 11 side or fall out. Furthermore,the exterior diameter of the stopper part 18 is made the same as theexterior diameter of the second tube 20 because when the bat iscompleted, the exterior surface of the stopper part 18 and the exteriorsurface of the second tube 20 are formed as the same surface.

The second tube 20 of the bat for baseball or softball related toembodiment one of the present invention is a cylindrical tube which hastwo open ends. The interior diameter of the second tube 20 is largerthan the exterior diameter of the impact part 12 of the first tube 15.More preferably, the interior diameter of the second tube 20 is abouttwice as large as the height of the crevice 60 formed between the firsttube 15 and the second tube 20 compared with the exterior diameter ofthe first tube 15. In addition, the second tube 20 may be formed fromthe same aluminum alloy or steel alloy as the first tube 15 or by alight material having excellent rebound characteristics such astitanium, a titanium alloy or magnesium alloy. Furthermore, the secondtube 20 may be formed by a material such as phosphor bronze, a copperalloy, a gold alloy or platinum alloy. Preferably, the second tube 20 isformed from one of the following; titanium, titanium alloy, magnesiumalloy or steel alloy. The second tube 20 is formed separately from thefirst tube 15 and is used after being separately heat treated.Therefore, compared to a usual double layered bat, heat treatment issimple and the particular difficulties involved with heat treating thefirst tube 15 and second tube 20 when they are formed from differentmaterial are removed. The second tube 20 with this material is fixed tothe exterior of the impact part 12 of the first tube 15 so that thecrevice 60 having a certain desired height is formed. In this way, whena ball is hit, ball transformation energy is absorbed by bending of theimpact part which has a double layered structure and the flight distanceof the ball can be further extended.

Although not shown in the diagrams, a make-up sheet can be applied tothe exterior of the above stated second tube 20 to the purpose ofprotecting the second tube 20 from damage and for design effect. Thismake-up sheet can be formed from, for example, a resin film such as apolyethylene film, an elastomer film and a plastic film or an FRP (FiberReinforced Plastics) sheet.

The fixing component 30 includes a body part 31 and an insertion part32. The insertion part 32 has a certain height. This height is theheight when the crevice 60 having a certain height is formed between thefirst tube 15 and the second tube 20 in the case where the insertionpart 32 is inserted between the first tube 15 and the second tube 20 andthe two tubes fixed by the adhesive 50. In other words, this height isset at a height after the height of the intervening hardened adhesive 50is subtracted from the certain height of the formed crevice 60.Furthermore, this insertion part 32 plays a role equivalent to thefulcrum of a spring when the second tube 20 bends when a ball is hit.

In the present embodiment a cap 40 is attached to the tip part 11 of thefirst tube 15 shown in FIG. 1 by press fit processing. When the bat isbeing used, it is usually thrown after a ball has been hit. In addition,depending on the user, there are times when the tip of bat hits a spikeor is dropped in dirt/mud and also hits the ground. The cap 40 acts toprotect the bat in these cases. That is, the cap 40 also acts to protectthe bat from damage caused by actions other than hitting a ball.

The cap 40 which fulfills this function is formed by a resin in thepresent embodiment and as stated above, is inserted into the tip of thefirst tube 15 by press fit processing. The cap 40 will be explained indetail while referring to FIG. 2. As is shown in FIG. 2, the cap 40 iscomprised of a cap tip part 41, a cap recessed part 42, a cap fixingpart 43 and a cap second fixing part 44. The cap tip part 41 protectsthe tip part 11 of the first tube 15 after the bat is formed.

The cap recessed part 42 plays the role of fixing the cap 40 to the tippart 11 of the first tube 15 in the case where the cap 40 is insertedinto the tip part 11 of the first tube 15 by press fit processing. Thatis, the exterior diameter of the cap recessed part 42 is smaller thanthe interior diameter of the curled part 19 of the tip part 11.Therefore, when press fitted, because the curled part 19 cuts into therecessed part 42 of the cap 40, the cap 40 fits onto the tip part 11 ofthe first tube 15.

The cap fixing part 43 has a larger exterior diameter than the interiordiameter of the curled part 19. Therefore, when the cap 40 is onceinserted into the tip part 11 of the first tube 15 by press fitprocessing, this cap fixing part 43 is hooked by the curled part 19 andthe cap 40 is prevented from jumping out. Furthermore, at the time ofpress fit processing, the interior of the tip part 11 of the first tube15 is applied with the adhesive 50, the adhesive hardens between theexterior of the cap fixing part 43 and the interior of the tip part 11of the first tube 15 and the cap 40 is more strongly fixed. In the sameway the cap second fixing part 44 plays the role of fixing the cap 40 tothe tip part 11 of the first tube 15 by the adhesive 50. The cap secondfixing part 44 increases the adhesion when the tip is formed accordingto the shape of the interior of the step part 17.

As stated above, the bat for baseball or softball related to embodimentone of the present invention is a double layered bat in which a secondtube is attached and fixed to the periphery of an impact part 12 of afirst tube 15. The fixing component 30 latches one end of this secondtube 20 to the first tube 15. FIG. 3 is an enlarged cross sectional viewin a longitudinal direction of a bat impact part and a taper part of abat for baseball or softball related to embodiment one of the presentinvention.

As is shown in FIG. 3, the fixing component 30 is formed from a fixingcomponent body 31 and an insertion part 32. The fixing component 30 is apart having a donut shape and a circular hollow space at its center.After the second tube 20 is attached to the first tube 15, the fixingcomponent 30 is attached to the exterior periphery of the first tube 15from the grip end side of the first tube 15. In addition, the insertionpart 32 of the fixing component 30 is inserted between the first tube 15and the second tube 20. At this time, both surfaces of the insertionpart 32 of the fixing component 30 and the interior surface of the bodypart 31 are applied with the adhesive 50. The fixing component 30 isfixed to the exterior periphery of the first tube 15 by hardening of theadhesive 50 and the second tube 20 is fixed to the exterior periphery ofthe insertion part 32 of the fixing component 30. Centrifugal force actson the exterior tube 20 (second tube) of the double layered bat which isformed when a ball is hit and so the exterior tube 20 tries to movetowards the bat tip side. Therefore, locking within the bat tip side ofthe second tube 20 is extremely important. On the other hand, acentrifugal force does not act in the direction of the grip side.Therefore, the latching in these parts does not require strength whencompared to latching in the tip part. Therefore, it is possible toobtain a sufficient amount of strength in latching by using the adhesive50.

Here, the thickness of the insertion part 32 of the fixing component 30is formed at a predetermined thickness. The adhesive 50 which is appliedto both surfaces of the insertion part 32 hardens and the first tube 15and second tube 20 are latched with a crevice 60 which has a certainheight. That is, this predetermined thickness is a thickness of thethickness to which the height of the adhesive 50 which hardens on bothsurfaces was subtracted from the thickness of the formed crevice 60. Inthis way, as stated above, the crevice 60 is formed with a desiredheight. Furthermore, the exterior surface of the body part 31 of thefixing component 30 is formed so that its diameter decreases smoothlytowards the taper part 13 of the first tube 15 and so that a protrusionis not formed on the exterior surface of the bat.

The above stated fixing component 30 is formed from a plastic orsynthetic rubber such as polyurethane, polyamide or polyethylene or adifferent elastomer material, however, the fixing component material isnot limited to this. A synthetic resin, metal or ceramic may also beused.

In FIG. 1, the crevice 60 is formed between the first tube 15 and thesecond tube 20 as stated above. That is, the crevice 60 is formed whenone end of the second tube 20 in which both ends are open is latched tothe periphery of a part between the step part 17 and the stopper part 18of the first tube 15 and the other end is latched to the periphery ofthe first tube 15 via the insertion part 32 of the fixing component 30which has a predetermined height. The crevice 60 can be betterunderstood by the cross sectional diagram in a width direction in FIG. 1(b). The crevice 60 is located between the second tube 20 and the firsttube 15 and is a space for reducing the consumption of impact energy asball transformation energy when the second tube 20 bends inwards when aball is hit. Furthermore, the height of this crevice 60 can be adjustedby a predetermined height (that is, a predetermined diameter) byreducing the diameter of the step part 17 (Or expanding the diameter bya processing method). In the present embodiment the height of thecrevice 60 is set between 0.1 mm-3.0 mm, for example, depending on thematerial etc, of the first tube 15 and the second tube 20.

[Effects of the Double Layered Bat]

The bat for baseball or softball having the above structure, related toembodiment one of the present invention is arranged with the crevice 60between the first tube 15 (interior tube) and the second tube 20(exterior tube). Then, the exterior tube 20 is formed from a metalhaving superior rebound characteristics than the interior tube 15.Therefore, when a ball is hit, mainly the exterior tube 20 bendsinwards, consumption of the impact energy as ball transformation energyis reduced and because the exterior tube 20 itself has superior reboundcharacteristics, the flight distance of the ball can be extended.

Second, the tip part 11 of the first tube 15 which acts as the bat's tipis formed from a metal tube, the rigidity of the bat tip part is high.For example, the rigidity of the bat is higher than that of the batcited in document three. Therefore, even if the ball is hit with the tipend side of this bat, the ball will fly. Furthermore, as stated above,because the bat is formed from metal up to the tip part, the thirdeffect is that durability of the bat is improved.

As stated above, because the cap 40 is inserted into the tip part 11 ofthe first tube 15 by press fit processing, processing becomes easy.Therefore, the fourth effect is that it is possible to reduce theoperational processes of the bat for baseball or softball related toembodiment one of this invention. In addition, there is no need to usecomplex processes in order to attach the parts and strict processingaccuracy of the tip part 11 of the first tube 15 is not demanded.Therefore, it is both possible to reduce the cost of the various partsand therefore the overall manufacturing costs of the bat.

Fifth, safety is improved in the bat for baseball or softball related toembodiment one of this invention. That is, in this bat as stated above,the exterior tube 20 is latched by the stopper part 18 of the metalinterior tube 15. Because both tubes are formed from metal, there is nosignificant difference in a coefficient of thermal expansion and theycan be securely latched by adjusting the interior and exterior diametersof the two tubes. Therefore, even if the resin cap 40 is damaged, aslong as the interior tube 15 itself is not damaged, the exterior tube 20will not come loose and jump out and thus safety is improved.

Sixth, the life cycle of the bat for baseball or softball related toembodiment one of this invention is much longer. The bat for baseball orsoftball related to embodiment one of this invention has a metal, doublelayered structure, however, the second tube 20 is attached and fixed viathe fixing component 30 with the adhesive 50. Therefore, it is possibleto easily replace the second tube 20 alone which can cause damage when aball is hit. In a conventional bat with a metal, double layeredstructure, because the exterior tube 20 (or the interior tube 15) islatched to the body 10 by a swaging process, even when the exterior tube20 (or the interior tube 15) is damaged, and it could not be replaced.The life cycle of the bat related to the present embodiment can be mademuch longer by replacing the exterior tube 20. Furthermore, because thesecond tube of the bat related to the present embodiment is manufacturedfrom metal, the effects of secular distortion are few and durability isexcellent compared to a hybrid type double layered bat.

The consumption of impact energy as ball transformation energy can bereduced by the present invention and in particular a bat for baseball orsoftball is proposed in which the strength of the bat tip part isreinforced and in addition a bat for baseball or softball is proposedwhich is inexpensive and can be easily manufactured.

Example One

An example of the bat for baseball or softball related to embodiment oneof the present invention will be explained. As stated above, the bat forbaseball or softball related to embodiment one of the present inventionincludes a cap. However, if the entire bat tip can be formed with thefirst tube 15, the durability of the bat tip part is increased. Thepresent example is an example of forming the bat tip part with the firsttube 15.

FIG. 4 is an enlarged cross sectional view in a longitudinal directionof a bat tip part of a bat for baseball or softball related to exampleone of embodiment one of the present invention. As is shown in FIG. 4,in the present example, the first tube 15 includes the step part 17 andthe stopper part 18 and the crevice 60 is formed between the first tube15 and the second tube 20. In this point, this is the same as the batfor baseball or softball related to embodiment one of the presentinvention.

In the bat in example one, the bat is formed with the first tube 15 upto the tip of the first tube (that is, bat tip) 15 from the stopper part18. First, the diameter of one end of the first tube 15, which has twoopen ends and a predetermined diameter of the impact part 12, is reducedby processing. As a result, the part from the taper part 13 of the firsttube 15 to the grip part 14 is formed. After this, the diameter of theother end of the first tube 15 is expanded by processing. As a result,the step part 17 and the stopper part 18 are formed. After this, thediameter of the other end of the first tube 15 is expanded by processingand the step part 17 and the stopper part 18 are formed. Next, withoutpassing through the process for forming the curled part 19, the tip partis closed off by a spinning process. In this way, it is possible to formthe bat of the present example which is formed by metal as far as thetip part. Because the second tube 20 and the fixing component 30 are thesame as in embodiment one of the present invention, an explanation herehas been omitted. Furthermore, the first tube 15 which has apredetermined diameter may be formed by first gradually reducing thediameter of the first tube 15 from the tip part 11, forming the partfrom the stopper part 18 to the grip part 14 and lastly closing the tippart 11.

Because the bat for baseball or softball related to example one havingthis structure is formed up to the tip part 11 with metal, the rigidityof the tip part 11 is further increased. In addition, because the bat isformed as one metal part up to the tip part 11, durability is alsofurther improved. The effects of increasing the flight distance of aball by a double layered structure having a crevice 60, improvingsafety, increasing the length of the life cycle of the bat andincreasing durability compared to a hybrid type bat, are the same as theabove stated embodiment one.

Example Two

Another example of the bat for baseball or softball related toembodiment one of the present invention will be explained. In the batfor baseball or softball related to embodiment one of the presentinvention, latching of the second tube 20 near the taper part 13 of thefirst tube 15 takes place by the fixing component 30 and the adhesive50. The second example of the bat for baseball or softball related toembodiment one of the present invention is an example of furtherstrengthening fixing of this fixing component to the first tube 15. FIG.5 is an enlarged cross sectional view in a longitudinal direction of abat impact part and a taper part of a bat for baseball or softballrelated to example two of embodiment one of the present invention.

As is shown in FIG. 5, the fixing component 30 related to example twoincludes a protrusion part 33 in addition to a body part 31 andinsertion part 32. Interlocking grooves 16 are formed by a spinningprocess on a predetermined place of the first tube 15.

The fixing method of the exterior tube 20 of the bat for baseball orsoftball related to the present example will be explained. First,interlocking grooves 16 are formed during the manufacturing process inpredetermined places on the first tube 15. Because the formation methodof the taper part 13 etc is the same, an explanation is omitted here.Next, the exterior tube 20 which has two ends which are open is attachedto the exterior periphery of the first tube 15 from the grip end sideand fixed to the exterior surface between the step part 17 and thestopper part 18 of the first tube 15 by the adhesive 50. Next, theadhesive 50 is applied to the interior of the donut shaped fixingcomponent 30 and then attached to the exterior periphery of the firsttube 15 from the grip end side of the first tube 15. The insertion part32 is inserted between the first tube 15 and the second tube 20 and theprotrusion part 33 is interlocked and fixed to the interlocking grooves16 which are formed in predetermined places of the first tube 15 andfixing is strengthened by hardening of the adhesive 50.

By interlocking and fixing the protrusion part 33 with the interlockinggrooves 16 of the first tube 15, it is possible to further strengthenfixing of the second tube 20 in the bat for baseball or softball relatedto the present example and safety is also improved. During processing ofthe first tube 15, the number of processes which form the interlockinggrooves 16 increases, however, there is no significant extension of theoperational processes. The effects of increasing the flight distance ofa ball by a double layered structure having a crevice 60, improvingsafety, increasing the length of the life cycle of the bat, increasingdurability and improving rigidity of the bat tip part compared to ahybrid type bat, are the same as the above stated embodiment one and anexplanation is omitted here.

Further, example two can be applied to the bat shown in example one. Inthis case the effects are the same as stated above.

Example Three

Another example of the bat for baseball or softball related toembodiment one of the present invention will be explained. As statedabove, in the bat for baseball or softball related to embodiment one ofthe present invention, in order to form the crevice 60 between the firsttube 15 and the second tube 20, the step part 17 is arranged on thefirst tube 15 by a diameter reducing process (or a diameter expandingprocess). However, if this process is omitted, it is possible to furtherreduce operational processes and a reduction in manufacturing costs. Thebat for baseball or softball related to example three does not includethe step part 17 and the crevice 60 is formed by a spacer 52. FIG. 6 andFIG. 7 are enlarged cross sectional views in a longitudinal direction ofthe tip part of the bat for baseball or softball related to examplethree of embodiment one of the present invention. FIG. 6 shows a batwith the cap 40 and FIG. 7 shows a bat without the cap.

As shown in FIG. 6 in the bat in example three, the impact part 12 ofthe first tube 15 extends as far as the tip part 11 and only the stopperpart 18 is formed without forming the step part 17. The formation of thecurled part 19 after this is also the same. Although the step part 17can be formed without difficulty by controlling a process machine whichsmoothly reduces or expands the diameter of the step part 17, theprocess requires certain period of time. Therefore, in order to reducethis process the bat in example three can be process by significantlyreducing the overall operational time.

Latching of the exterior tube 20 of the bad related to example threewill be explained. As stated above, the bat of the present example doesnot include the step part 17, therefore, the crevice 60 exists betweenthe impact part 12 of the first tube 15 and the second tube 20. It isdifficult to bury the crevice 60 using only the adhesive 50. Thus, thebat in example three, the first tube 15 and the second tube 20 are fixedby the adhesive 50 via the spacer which has a predetermined height. Theheight of this spacer 52 is equal to the height of the crevice 60 whichis formed between the first tube 15 and the second tube 20.

The spacer 52 is a part which has a hollow center and donut typecylindrical shape, the exterior periphery of the bottom part (not shownin the diagram) is large and the exterior diameter of a side wall part(not shown in the diagram) which extends from the bottom part, issmaller than the exterior diameter of the bottom part. Morespecifically, the exterior diameter of the bottom part is formed to thesame diameter as the exterior diameter of the first tube 15 between thestopper part 18 and the curled part 19 and the exterior diameter of theside wall part is a diameter in which the exterior diameter of thebottom part has been reduced slightly more than the thickness of thesecond tube 20. That is, the height of the wall part of the spacer 52 isa little lower than the certain height of the crevice 60 formed.Therefore, the thickness of the side wall part of the spacer 52 plays arole equivalent to a fulcrum of a spring when the second tube 20 bendswhen a ball is hit. Furthermore, the material of the spacer 52 is notlimited, however, particularly because it is a part which is arrangedbetween the side wall surface of the stopper part 18 of the first tube15 and the second tube 20, it is preferably formed from a materialhaving soundproof characteristics so that a metal sound is not producedwhen the metal tubes contact.

Next, the latching method of the second tube 20 which used the spacer 52will be explained. The spacer 52 which has the adhesive 50 applied toits entire surface is attached to the first tube 15 from the grip endside. The back surface of the bottom part of the spacer 52 is attachedto the stopper part 18 of the first tube 15 by the adhesive 50. Next,before the adhesive 50, which is applied to the spacer 52, hardens, thesecond tube 20 is attached to the first tube 15 from the grip end side.The height (thickness) of the side wall part of the spacer 52 is smallerthan the height of the crevice 60 which is formed. Therefore, the secondtube 20 is attached so that it covers the side wall part of the spacer52. The second tube 20 is fixed and the crevice 60 is formed between theimpact part 12 of the first tube 15 and the second tube 20 when theadhesive 50 which is applied, hardens. Furthermore, because theinsertion process of the cap 40 is the same as in the above statedembodiment one, an explanation is omitted here.

Because process of processing the step part of the bat for baseball orsoftball related to example three having the above stated structure, isomitted, it is possible to further reduce operational processes.Therefore, it is also possible to further reduce manufacturing costs. Inaddition, the effects of increasing the flight distance of a ball by adouble layered structure having a crevice 60, improving safety,increasing the length of the life cycle of the bat, increasingdurability and improving rigidity of the bat tip part compared to ahybrid type bat, are the same as the above stated embodiment one and anexplanation is omitted here.

Furthermore, example three can also be applied to the bat shown inexample one. This example is shown in FIG. 7. The manufacturing processand the effects of this example are the same as those stated above andthus an explanation is omitted here. Furthermore, it is also possible touse the fixing component 30 of the bat in example three which is shownin FIG. 6 and FIG. 7 as the fixing component 30 which has the protrusionpart 33 shown in example two. In this case, the effects andmanufacturing method are the same as in example two and thus anexplanation is omitted here.

Embodiment Two

The bat for baseball or softball related to embodiment two of thepresent invention will be explained. As stated above, the bat forbaseball or softball related to embodiment one of the present inventionis a double layered bat which has a crevice 60. By forming the bat byfixing two thin metal tubes so that a crevice is formed, and when thethin metal tubes bend inwards when a ball is hit it is possible toreduce consumption of impact energy as ball transformation energy. Byincreasing the exterior tube 20 forming a three layered structure, it ispossible to further reduce the thickness of each tube respectively. Inaddition, by a synergistic effect of the bending of each exterior tubeit is possible to further increase the flight difference of a ball. Thebat for baseball or softball related to embodiment two of the presentinvention is a three layered bat. FIG. 8 is a longitudinal directionnotch sectional view and a cross sectional view of the line β-β′ in awidth direction of a bat for baseball or softball related to embodimenttwo of the present invention.

As is shown in FIG. 8, the bat for baseball or softball related toembodiment two of the present invention is comprised of a first tube 15,a second tube 20, a third tube 25, a fixing component 30 and a cap 40.The third tube 25 is added to the bat for baseball or softball relatedto embodiment one of the present invention and thus there is no largedifference between the structure which is explained in the preferredembodiment. However, because the structure of the first tube 15 and thefixing component 30 is changed to correspond with the three layered bat,this point will be explained in detail. Furthermore, because the sameparts as those of the bat for baseball or softball related to embodimentone of the present invention have the same symbols, an explanation willbe omitted here.

In order to latch the two exterior tubes (second tube 20 and third tube25) of the three layered bat, the first tube 15 of the bat for baseballor softball related to embodiment two of the present invention has afirst stopper part 18 a, a second stopper part 18 b and a step part 17.Each of these parts is manufactured by reducing or expanding theirrespective diameters by a swaging process etc. in the same way as thebat for baseball or softball related to embodiment one of the presentinvention. However, for example, after forming the second stopper part18 b in a first place the first stopper part 18 a is formed by reducingthe certain height (that is, reducing the certain diameter) in a secondplace 82 (not shown in the diagram) in the case where manufacturing isperformed by a diameter reducing process. This certain height is equalto the height of the crevice 60 which is formed between the third tube25 and the second tube 20 in addition to the thickness of the secondtube 20.

Furthermore, the step part 17 is formed by gradually reducing thecertain height (diameter) of the first tube 15 in the direction of thegrip end from a third place 83 which is a certain length from the firststopper part 18 a towards the grip end up to a fourth place 84. Thecertain height at this time is the height of the crevice 60 which isformed between the second tube 20 and the first tube 15. The impact part12 is formed by extending the same diameter of the first tube 15 fromthe fourth place 84 up to a fifth place 85 and the taper part 13 and thegrip part 14 are formed by further reducing the diameter of the firsttube 15 from the fifth place 85. The process which formed the curledpart 19 on the tip part 11 is the same as in the bat for baseball orsoftball related to embodiment one of the present invention. Inaddition, the length of the curled part 19 can be any length as long asit is sufficient to latch the cap 40 which is later inserted by pressfit processing. The length of the curled part 19 is about 3 mm-10 mm ormore preferably about 5 mm.

The fixing component 30 includes a body part 31, an insertion part 32, afirst stopper part 34 and a second stopper part 35. The first stopperpart 34 and the second stopper part 35 are formed in a step-like shapefrom the insertion part 32 which has a certain thickness (equal to theheight of the crevice 60 which is formed between the second tube 20 andthe first tube 15 stated above) which is different to the fixingcomponent 30 in embodiment one of the present invention. The height ofthe first stopper part 34 which is formed in a step-like shape is a sumof the height of the crevice 60 which is formed between the second tube20 and the third tube 25 and the thickness of the second tube 25. Inaddition, the height of the second stopper part 35 is set at a heightroughly equivalent to the thickness of the third tube 25. In this way,the crevice 60 of a certain height is formed between the third tube 25and the second tube 20 and also between the second tube 20 and the firsttube 15. In addition, the exterior surface of the third tube 25 and theexterior surface of the fixing component 30 are formed as one surface.Furthermore, the height of the crevice 60 is appropriately set accordingto the material used in the first tube 15, the second tube 20 and thethird tube 25. In embodiment two of the present invention, the height ofthe crevice 60 is set, for example, between about 0.1 mm-3.0 mm.

The first tube 15, the second tube 20 and the third tube 25 of the threelayered bat of embodiment two are cylindrical metal tubes which have twoopen ends respectively. The first tube 15 and the second tube 20 aregenerally formed from an aluminum alloy or steel alloy in order tosecure lightness and strength. From the viewpoint of ease of processingand cost, the material is preferably an A7000 aluminum alloy such asaluminum alloy AA7050, AA7046 regulated under the American AluminumAssociation Regulation. In addition the third tube 25 can be formed froman aluminum alloy or steel alloy the same as the first tube 15 or from amaterial such as titanium, a titanium alloy or magnesium alloy which arelight and have excellent rebound characteristics. Furthermore, the thirdtube 25 can be formed from a phosphor bronze, a copper alloy, a goldalloy, or a platinum alloy. Preferably, the third tube 25 is formed fromone of titanium, a titanium alloy, a magnesium alloy or a steel alloy.Furthermore, the thickness of the first tube 15, the second tube 20 andthe third tube 25 related to embodiment two is formed thinner than thethickness of the first tube 15 and the second tube 20 of the bat forbaseball or softball relate to embodiment one of the present invention.This is because the bat is three layered and in order to lighten eachtube and make the entire bat a predetermined weight. In addition,because the bat has three layers and because it is possible to secure acertain strength by the three tubes, it is possible to lighten the batby making each one of the tubes thinner.

By making the bat for baseball or softball related to embodiment two athree layered structure it is possible to further reduce the thicknessof each exterior tube and it is also possible to further improve theflight distance of a ball by a synergistic effect of the bending of eachof the tubes. In addition, the effects of improving safety, increasingthe length of the life cycle of the bat compared to a hybrid type bat,improving rigidity of the bat tip part and increasing durability, arethe same as the above stated embodiment one. Furthermore, because twostopper parts 18 are formed in the processing of the first tube 15, thenumber of processes increases, however, because it is a process which ismachine controlled, there are hardly any effects. The three layered batrelated to embodiment two can reduce operational processes compared to aconventional hybrid bat and the bat cited in Patent Document three.

Furthermore, the bat for baseball or softball related to embodiment twocan also be transformed into example one, example two and example threeof the bat for baseball or softball related to embodiment one statedabove. That is, the tip part 11 is formed by the first tube 15 and thecap 40 is omitted, the protrusion part 33 is arranged on the fixingcomponent 30, the latching of the second tube 20 and the third tube 25is further strengthened and it is possible to omit forming the step part17 of the first tube 15 by using the spacer 52. In addition, the effectsof each are the same as the transformation example of the bat forbaseball or softball related to embodiment one.

Embodiment Three

The bat for baseball or softball related to embodiment three of thepresent invention will be explained. As stated above, the bat forbaseball or softball related to embodiment one of the present inventionis a double layered bat arranged with a crevice 60 between an exteriortube 20 (second tube) and a first tube 15. By this structure it ispossible to reduce consumption of impact energy as ball transformationenergy when the thin metal tubes bend inwards when a ball is hit. And,by using a material which has excellent rebound characteristics as thematerial of the exterior tube 20 (second tube), for example, titanium ora titanium alloy, the bat is further constructed to improve the flightdistance of a ball. However, this titanium or titanium alloy isexpensive and if the entire second tube 20 is formed form titanium or atitanium alloy, manufacturing costs increase significantly. Therefore,if the exterior tube 20 (second tube) is formed from a plurality oftubes and titanium or a titanium alloy is used only on a sweet spotwhich is the center of an impact with a ball, then an increase in costscan be controlled. The bat for baseball or softball related toembodiment three is a bat which has a double layered structure having anexterior tube 20 which is comprised of a plurality of tubes. FIG. 9 is alongitudinal direction surface view and a longitudinal direction notchsectional view of a bat for baseball or softball related to embodimentthree of the present invention.

As is shown in FIG. 9, the bat for baseball or softball related toembodiment three is comprised of a first tube 15, a second tube 20 whichis comprised of three tubes (second tube A20 a, second tube B20 b andsecond tube C20 c), a fixing component 30 and a cap 40. In addition, inorder to latch the three tubes of the second tube 20 while forming thecrevice 60, a second fixing component 36 is used. Because the first tube15, the fixing component 30 and the cap 40 are the same as in the batfor baseball or softball related to embodiment one of the presentinvention stated above, the same parts have the same symbols and anexplanation is omitted here.

The second tube 20 of the bat for baseball or softball related toembodiment three is comprised of three tubes, second tube A20 a, secondtube B20 b and second C20 c as shown in FIG. 9. However, FIG. 9 is onlyan example and the number of second tubes is not limited to three. Inembodiment three, the second tube A20 a and the second tube C20 c areformed from the same material as the first tube 15, namely an aluminumalloy or a steel alloy. From the viewpoint of ease of processing andcost, the material of the first tube 15 is preferably an A7000 aluminumalloy such as aluminum alloy AA7050, AA7046 regulated under the AmericanAluminum Association Regulation. The second tube B20 b is the part whichis equivalent to what is called the sweet-spot where the ball travelsfurthest when hit, and is formed from high cost titanium or a titaniumalloy which has excellent rebound characteristics. The second tube B20 bmay be formed from a magnesium alloy, phosphor bronze, a copper alloy, agold alloy, or a platinum alloy etc. The plurality of second tubes arecylindrical and each tube formed with two ends which are open. Thesecond tubes are each heat treated separately and used once stress isreleased. Furthermore, either the second tube A20 a or the second tubeC20 c may be formed from the same material as the second tube B20 b. Asa result, at least one of the three second tubes (20 a, 20 b, 20 c) isformed from a different material to the other two tubes. In addition,the three second tubes (20 a, 20 b, 20 c) are formed to the samethickness.

The second fixing component 36 is a convex fixing component in a crosssection longitudinal direction and is formed from a resin the same asthe fixing component 30. More specifically, the second fixing component36 is formed from a plastic or synthetic rubber such as polyurethane,polyamide or polyethylene or a different elastomer material, however,the material of the second fixing component 36 is not limited to this. Asynthetic resin, metal or ceramic may also be used. The second fixingcomponent 36 is preferably formed from a material having soundproofcharacteristics so that a metal sound is not produced when the firsttube 15 and the three second tubes 20 contact when a ball is hit.

Here, the bottom part (not shown in the diagram) of the second fixingcomponent 36 has a certain thickness and this thickness is equivalent tothe height of the crevice 60 which is formed between the first tube 15and the plurality of the second tubes 20. Furthermore, the bottom partof the second fixing component 36 plays a role equivalent to a fulcrumof a spring when the second tube 20 bends when a ball is hit. Inaddition, the convex shaped protrusion part (not shown in the diagram)of the second fixing component 36 also has a certain height which isequivalent to the thickness of each of the three second tubes 20 (20 a,20 b, 20 c). Therefore, the crevice 60 with a certain height is formedbetween the first tube 15 and the plurality of second tubes 20 in thecase where the three second tubes 20 (20 a, 20 b, 20 c) are fixed to theexterior periphery of the impact part 12 of the first tube 15 via thesecond fixing component 36 and the adhesive 50. In addition, theexterior surface of the three second tubes 20 (20 a, 20 b, 20 c), thetip part 11 and the taper part 13 of the first tube 15 and the uppersurface of the convex shaped protrusion of the second fixing component36 are formed as the same surface.

Next, the attachment method of the three second tubes 20 (20 a, 20 b, 20c) will be explained. A first tube 15 is formed in the same way as thebat for baseball or softball related to embodiment one of the presentinvention stated above. Next, using two fixing components 36, the threesecond tubes 20 (20 a, 20 b, 20 c) are fixed via the second fixingcomponents 36 and the adhesive 50. In this way, the three second tubes20 (20 a, 20 b, 20 c) become one second tube 20. This process can beperformed before the processing of the first tube 15 and can also beperformed in parallel to the processing of the first tube 15 by adifferent production line. Next, the second tube 20 which has become onetube is attached to the exterior periphery of the impact part 12 of thefirst tube 15 from the grip end side of the first tube 15. At this time,the adhesive 50 is applied to the exterior surface from the step part 17of the first tube 15 to the stopper part 18 and also applied to thebottom surface of the second fixing component 36. Next, the adhesive 50is applied to the bottom surface of the body part 31 of the fixingcomponent 30 and the entire surface of the insertion part 32 and thefixing component 30 is inserted between the first tube 15 and the secondtube 20 from the grip end side of the first tube 15. When the adhesive50 hardens, the second tube 20 is fixed to the impact part 12 of thefirst tube 15 and a double layered bat having three second tubes 20 (20a, 20 b, 20 c) is formed. Because the process of press fitting the cap40 is the same as embodiment one stated above and explanation is omittedhere.

In the bat for baseball or softball related to embodiment three of thepresent invention which has the structure explained above, by arrangingthe second tube 20 b which is formed from titanium or a titanium alloyhaving excellent rebound characteristics only in a sweet-spot positionwhich when hit can increase the flight distance of a ball, it ispossible to reduce and increase in manufacturing costs even if expensivetitanium or a titanium alloy is used. In addition, it is possible toform the other second tubes (20 a, 20 c) with a cheaper metal such as asteel alloy and thus it is possible to propose a two layered bat inwhich a reduction in manufacturing costs can easily be overlapped.

Furthermore, the second tube 20 b which has excellent reboundcharacteristics is arranged only on the sweet-spot part and the othersecond tubes (20 a, 20 c) for example, can be formed with a metal whichhas poorer rebound characteristics than an aluminum alloy or a steelalloy. In this case, the bat becomes a bat in which a ball does nottravel as far if hit in a place other than this sweet-spot, however,this bat can be preferably used as a practice bat for batting skillacquisition.

In addition, the effects of increasing the flight distance of a ball bya double layered structure, reducing operational processes, improvingsafety, increasing the length of the life cycle of the bat compared to ahybrid type bat, increasing durability and improving rigidity of the battip part, are the same as in the above stated embodiment one andembodiment two of the present invention and an explanation is omittedhere. Furthermore, a transformed example is possible as in embodimentone and embodiment two of the present invention stated above wherein thecap 40 can be omitted by forming the tip part 11 with the first tube 15,latching of the second tube 20 can be strengthened by arranging a convexshaped protrusion on the fixing component 30 and formation of the steppart 17 of the first tube 15 can be omitted by using the spacer 52. Inaddition, each of these effects is the same as in the transformedexamples of the bat for baseball or softball related to embodiment onestated above.

Embodiment Four

Next, the bat for baseball or softball related to embodiment four of thepresent invention will be explained. As stated above, the second tube 20in the double layered bat related to embodiment three of the presentinvention is comprised of a plurality of tubes and the second tube 20 bwhich is formed from titanium or a titanium alloy having excellentrebound characteristics, is arranged in the sweet-spot position. In thebat for baseball or softball related to embodiment four of the presentinvention, the arrangement of the second tube 20 which is formed fromtitanium or a titanium alloy having excellent rebound characteristics inthe sweet-spot position is the same as in embodiment three, however, inembodiment four this second tube 20 is comprised from one tube. FIG. 10is a longitudinal direction surface view and a longitudinal directionnotch sectional view of a bat for baseball or softball related toembodiment four of the present invention.

As is shown in FIG. 10, the bat for baseball or softball related toembodiment four of the present invention is comprised of a first tube15, a second tube 20 and a cap 40. That is, unlike the bat for baseballor softball related to embodiment one, two and three of the presentinvention, there is no need for a fixing component 30. The second tube20 is latched by two stopper parts (18 a, 18 b) which are arranged onthe first tube 15.

In the bat for baseball or softball related to embodiment four of thepresent invention, the second tube 20 is short, about half the length ofthe impact part 12 of the first tube 15. Two step parts 17 and twostopper parts 18 (first step part 17 a and second step part 17 b, firststopper part 18 a and second stopper part 18 b) of the first tube 15 areformed and the distance from the bat tip to the first stopper part 18 ais extended. In this way, the length of the second tube 20 which isattached and fixed between the first stopper part 18 a and secondstopper part 18 b of the first tube 15 can be reduced. Furthermore, thecap 40 does not include a cap second fixing component 44. Because theother parts are the same as in the bat related to embodiment one statedabove, the same parts have the same symbols and an explanation isomitted here.

Next, the formation method of the first tube 15 of the bat related toembodiment four will be explained. The material and thickness of thefirst tube 15 and the second tube 20 are the same as in embodiment onestated above therefore an explanation is omitted here. The first tube 15is formed by a combination of diameter reducing and diameter expandingby a swaging process for example and this is different to the formationof the first tube 15 of the bat related to embodiments one, two andthree of the present invention stated above.

First, a cylindrical tube (first tube 15) having two ends which are openand which has a diameter within the range regulated by baseballregulations is prepared. Next, the diameter of the tube is reduced by acertain height (diameter) at a first place of a certain distance fromone end of the tube. This first place is the first stopper 18 a. Thesweet-spot position of the double layered bat which is formed is set asa base and this distance is decided taking the material etc of the firsttube 15 and second tube 20 into consideration. In addition, the certainheight is equivalent to the thickness of the second tube 20.

Next, a diameter of the tube is smoothly reduced a certain height(diameter) by processing from a second place (not shown in the diagram)a certain distance from the first stopper 18 a towards the grip end upto a third place (not shown in the diagram). The first step part 17 a isthe part between this second place and third place and the certainheight is equivalent to the height of a crevice 60 which is formedbetween the first tube 15 and the second tube 20.

Furthermore, the diameter of the first tube 15 is processed at the samediameter from the third place a certain distance up to a fourth place(not shown in the diagram) towards the grip end. Next, the diameter ofthe first tube 15 is smoothly expanded a certain height (diameter) fromthe fourth place up to a fifth place (not shown in the diagram). Thepart from the fourth place to the fifth place is the second step part 17b. Furthermore, this height is equivalent to the height of a crevice 60which is formed between the first tube 15 and the second tube 20.

Next, an adhesive 50 is applied to the exterior surface of this tubebetween the first stopper part 18 a and the first step part 17 a. Andthe adhesive 50 is applied to the exterior surface of the tub from thesecond step part 17 b a certain distance up to a sixth place towards thegrip end. Then, before the adhesive 50 hardens, this tube is insertedfrom the other end of the tube towards the first stopper part 18 awithin the second tube 20 which is formed in advance to a lengthcorresponding to the distance of the sweet-spot.

Here, the exterior diameter of the second tube is the same as theexterior diameter of the part between one end of the above stated tube(first tube 15) and the first place. In addition, the interior diameterof the second tube is a slightly larger than the exterior diameterbetween the first stopper part 18 a and the second place which areformed on the above stated tube (first tube 15), and slightly largerthan the exterior diameter between the fifth place and the sixth place.Therefore, the second tube 20 covers the exterior surface of the firsttube 15 from the first stopper part 18 a up to the sixth place and theexterior surface of the tip part 11 of the first tube 15 and theexterior surface of the second tube 20 are formed into one surface.

After the adhesive 50 hardens and the second tube 20 is fixed to theexterior periphery of the impact part 12 of the first tube 15, thediameter of the first tube 15 is further expanded a certain height(diameter) in the sixth place. The sixth place is the second stopperpart 18 b and the position of the sixth place is the position of an endpart (other end part) which is located on the opposite side of an endpart of the first stopper part 18 a side of the second tube 20 which isattached. In addition, the certain height is a height equivalent to thethickness of the second tube 20. In this way, the other end of thesecond tube 20 is latched by the adhesive 50 between the second steppart 17 b and the second stopper part 18 b. In addition, the second tube20 is prevented from moving back and forth by the first stopper part 18a and the second stopper part 18 b. Then, a crevice 60 having a certainheight is formed by the first step part 17 a and the second step part 17b between the impact par 12 of the first tube 15 and the second tube 20.

Furthermore, after this a taper part 13 and a grip part 14 are formed bya diameter reducing process and when lastly the grip end is formed by aspinning process, the first tube 15 is formed. After this, the firsttube 15 is heated while the second tube 20 is still attached, stress inreleased and the bat having a certain strength is formed. This heattreatment should be applied to the first tube 15 and preferably shouldbe performed by controlling the temperature so that there is no effecton the adhesive 50 which has hardened. Because heat treatment is notperformed simultaneously on both the first tube 15 and the second tube20 which have different materials as in the bat shown in Patent Documentone, control of the heat treatment process is easy. Next, when the cap40 is processed by press fitting the bat related to embodiment four iscompleted. Furthermore, because the cap 40 can secure a sufficientlength of the cap fixing component 43, there is no need to form thesecond fixing component 44.

The bat related to embodiment four having the above described structurehas a structure in which the second tube 20 is only attached to theposition of the sweet-spot as can be judged from the notch cross sectionin FIG. 10 (b). That is, because a tube which is formed from a metalhaving excellent rebound characteristics is used only on the part whichmakes a ball travel far when hit, an increase in manufacturing costs canbe reduced.

In addition, the effects of increasing the flight distance of a ball bya double layered structure having a crevice 60, improving rigidity ofthe bat tip part, improving safety, increasing the length of the lifecycle of the bat compared to a hybrid type bat and increasing durabilityare the same as in the bat in the above stated embodiment one,embodiment two and embodiment three of the present invention.

However, Because the first tube 15 of the bat related to embodiment fouris formed by a combination of a diameter reducing process and a diameterexpanding process, the operational processes increase compared to thebat related to embodiments one, two and three of the present invention.

Furthermore, the bat related to the present embodiment can betransformed as an example the same as in the above stated example oneand example three of the embodiment one of the present invention. Theeffects in this case are also the same. In addition, as explained inembodiment three, the first tube 15 can be formed from a metal which haspoorer rebound characteristics than an aluminum alloy a steel alloy andcan be used as a practice bat for batting skill acquisition. The effectsin this case are also the same.

1. A bat for baseball or softball comprising: a first tube having a grippart, a taper part, an impact part and a tip part, a step part having alarger exterior diameter than an exterior diameter of said impact part,a first stopper part having a larger exterior diameter than an exteriordiameter of said step part and said first tube also including a secondstopper part having a larger exterior diameter than said exteriordiameter of said first stopper part; a cylindrical second tube havingtwo ends which are open, and having an interior diameter which is largeran exterior diameter of said step part of said first tube and smallerthan said exterior diameter of said first stopper part of said firsttube; a cylindrical third tube having two ends which are open, and alsohaving an interior diameter which is larger than an exterior diameter ofsaid second tube and smaller than said exterior diameter of said secondstopper part of said first tube; a fixing component including a bodypart, an insertion part and a fixing component stopper part, saidinsertion part being inserted between said first tube and said secondtube, and said fixing component stopper part which forms a crevicebetween said second tube and said third tube, said fixing componentlatching said second tube and said third tube to an exterior peripheryof said first tube; a first crevice located between said second tube andsaid first tube, said first crevice being formed by said second tubebeing attached to an exterior periphery of said impact part of saidfirst tube, one end of said second tube being fixed between said steppart of said first tube and said first stopper part by an adhesive, andthe other end of said second tube being fixed by said adhesive with saidinsertion part of said fixing component, said fixing component beinginserted between said second tube and said first tube; and a secondcrevice located between said third tube and said second tube, saidsecond crevice being formed by said third tube being attached to anexterior periphery of said second tube, one end of said third tube beingfixed between said first stopper part of said first tube and said secondstopper part by said adhesive and the other end of said third tube beingfixed by said adhesive with said fixing component stopper part of saidfixing component.
 2. The bat for baseball or softball according to claim1, further comprising a cap, said cap having a cap tip part, a recessedpart and a fixing part, a tip of said tip part of said first tube havinga curled part which curves inwards, and an exterior diameter of saidfixing part of said cap being smaller than an interior diameter of saidfirst tube from said curled part to said second stopper part, and anexterior diameter of said recessed part of said cap being smaller thanan interior diameter of said curled part of said first tube and saidrecessed part being latched by said curled part.
 3. The bat for baseballor softball according to claim 1, wherein a tip of said tip part curvesinwards and is closed.
 4. The bat for baseball or softball according toclaim 1, further comprising a spacer, said spacer being inserted betweensaid first tube and said second tube and also between said second tubeand said third tube, said first tube includes a first stopper parthaving an exterior diameter which is larger than an interior diameter ofsaid second tube and which is smaller than an interior diameter of saidthird tube, and also includes a second stopper part having an exteriordiameter which is larger than said exterior diameter of said firststopper part and which is larger than said interior diameter of saidthird tube, said second tube is attached to an exterior periphery ofsaid impact part of said first tube, and one end of said second tube isfixed to a tip of a first stopper part side of said impact part of saidfirst tube by said adhesive and said spacer, and the other end of saidsecond tube being fixed by said adhesive with said insertion part ofsaid fixing component, and said first crevice being formed between saidsecond tube and said first second tube, and said third tube is attachedto an exterior periphery of said second tube, and one end of said thirdtube is fixed between said first stopper part and said second stopperpart by said adhesive and said spacer, and the other end of said thirdtube being fixed by said adhesive with said fixing component firststopper part of said fixing component, and said second crevice beingformed between said third tube and said second tube.
 5. The bat forbaseball or softball according to claim 2, wherein said first tubeincludes a groove in a place of a taper part side of said impact part,said fixing component further having a protrusion part on a side inwhich said insertion part faces said first tube, said fixing componentbeing inserted between said first tube and said second tube, and alsobetween said second tube and said third tube, and said protrusion partbeing fitted with said groove of said first tube.
 6. The bat forbaseball or softball according to claim 5, wherein said first tube isformed from an aluminum alloy or an alloy steel and one of either saidsecond tube or said third tube is formed from titanium, a titaniumalloy, a magnesium alloy or an alloy steel.
 7. A bat for baseball orsoftball comprising: a first tube having a grip part, a taper part, animpact part, a tip part, a step part having a larger exterior diameterthan an exterior diameter of said impact part and said first tube alsoincluding a stopper part having a larger exterior diameter than saidexterior diameter of said step part; a plurality of cylindrical secondtubes each having two ends respectively, said ends being open, and eachof the plurality of second tubes having an interior diameter and anexterior diameter which are the same respectively, said interiordiameter of each of the plurality of second tubes being larger than saidexterior diameter of said step part of said first tube and smaller thansaid exterior diameter of said stopper part of said first tube, and atleast one of said plurality of second tubes being formed from a materialwhich is different to the other tubes; a first fixing componentincluding a body part and an insertion part, said insertion part beinginserted between said first tube and said second tube, said first fixingcomponent latching said second tube to an exterior periphery of saidfirst tube; a second fixing component latching said plurality of secondtubes to said exterior periphery of said first tube; and a crevicelocated between said first tube and said plurality of second tubes, saidcrevice being formed by each of said plurality of second tubes beingattached to the exterior periphery of said impact part of said firsttube, an end of one of said plurality of second tubes being fixedbetween said step part of said first tube and said stopper part by anadhesive, the other end of one of said plurality of second tubes beingfixed by said adhesive with said second fixing component, an end ofanother one of said plurality of second tubes being fixed by saidadhesive with said second fixing component, the other end of another oneof said plurality of second tubes being fixed by said adhesive with saidfirst fixing component, and both ends of yet another one or more secondtubes of said plurality of second tubes being fixed by said adhesivewith said second fixing component.
 8. The bat for baseball or softballaccording to claim 7, further comprising a cap, said cap having a captip part, a recessed part and a fixing part, a tip of said tip part ofsaid first tube having a curled part which curves inwards, and anexterior diameter of said fixing part of said cap being smaller than aninterior diameter of said first tube from said curled part to saidstopper part, and an exterior diameter of said recessed part of said capbeing smaller than an interior diameter of said curled part of saidfirst tube and said recessed part being latched by said curled part. 9.The bat for baseball or softball according to claim 7, wherein a tip ofsaid tip part curves inwards and is closed.
 10. The bat for baseball orsoftball according to claim 7, further comprising a spacer, said spacerbeing inserted between said first tube and one of said plurality of saidsecond tubes, said first tube includes only a stopper part having alarger exterior diameter than an exterior diameter of said impact partand a larger exterior diameter than an interior diameter of each of saidplurality of second tubes, and each of said plurality of second tubes isattached to an exterior periphery of said impact part of said first tuberespectively, wherein a crevice being formed between said first tube andsaid plurality of second tubes, by an end of one of said plurality ofsecond tubes being fixed between said step part of said first tube andsaid stopper part by an adhesive and a spacer, the other end of one ofsaid plurality of second tubes being fixed by said adhesive with saidsecond fixing component, and an end of another one of said plurality ofsecond tubes being fixed by said adhesive with said second fixingcomponent, the other end of another one of said plurality of secondtubes being fixed by said adhesive with said first fixing component, andboth ends of yet another one or more second tubes of said plurality ofsecond tubes being fixed by said adhesive with said second fixingcomponent.
 11. The bat for baseball or softball according to claim 8,wherein said first tube includes a groove in a place of a taper partside of said impact part, said fixing component further having aprotrusion part on a side in which said insertion part faces said firsttube, said fixing component being inserted between said first tube andone of said plurality of second tubes, and said protrusion part beingfitted with said groove of said first tube.
 12. The bat for baseball orsoftball according to claim 11, wherein said first tube is formed froman aluminum alloy or an alloy steel and at least one of said pluralityof second tubes is formed from titanium, a titanium alloy, a magnesiumalloy or an alloy steel.